Rework system menu options

[ivanderk]

Added by @amarinso

"...I think system is too generic and options below it are a bit misleading

system > install ==> installs devcon on the system. I propose to change name to "install devcon", so users don't have to go inside the option to know what is doing the option

system > update ==> maybe should be "configure environment" because really... we are not doing a "system update" ... it seems it's going to update windows :-) ..."